Enhanced photoelectrochemical performance of 2D core-shell WO3/CuWO4 uniform heterojunction via in situ synthesis and modification of Co-Pi co-catalyst

In order to enhance the photoelectrochemical (PEC) performance of tungsten oxide (WO₃), it is critical to overcome the problems of narrow visible light absorption range and low carrier separation efficiency. In this work, we firstly prepared the 2D plate-like WO₃/CuWO₄ uniform core-shell heterojunction through in-situ synthesis method. After modification with the amorphous Co-Pi co-catalyst, the ternary uniform core-shell structure photoanode achieved a photocurrent of 1.4 mA/cm² at 1.23 V vs. RHE, which was about 6.67 and 1.75 times higher than that of pristine WO₃ and 2D uniform core-shell heterojunction, respectively. Furthermore, the onset potential of 2D WO₃/CuWO₄/Co-Pi core-shell heterojunction occurred a negatively shifts of about 20 mV. Experiments illuminated that the enhanced PEC performance of WO₃/CuWO₄/Co-Pi photoanode was attributed to the broader light absorption, reduced carrier transfer barrier and increased carrier separation efficiency. The work provides a strategy of maximizing the advantages of core-shell heterojunction and co-catalyst to achieve effective PEC performance.